Recently, the downsizing, lightening, and thinning of various electronic components have advanced rapidly along with the speeding-up and higher integration of LSIs and the larger capacity of memories. Therefore, excellent heat resistance, dimensional stability, electrical properties, or the like are also demanded in materials therefor.
Thermosetting resins, such as phenol resins, epoxy resins, and polyimide resins, have conventionally been used for printed wiring boards. These resins have various performances in a balanced manner, but have poor dielectric properties in a high frequency range. As a novel material to solve the above problem, polyphenylene ether gathers attention, and attempts have been made to apply polyphenylene ether to a metal-clad laminate (Patent Document 1).